[CLOSED] $20,000 Mini-Blockchain Implementation

[bitfreak!]

This bounty is now closed as per the last update. If you have any questions please send me a PM.

[bitfreak!]

Also, I feel like developers will be much more willing to work on fulfilling these bounties if I can provide some way of ensuring that they will be rewarded the bounty upon completing the task, but I'm not really sure the best way of doing that. So if you have any good ideas relating to that let me know.

[BitcoinFr34k]

Also, I feel like developers will be much more willing to work on fulfilling these bounties if I can provide some way of ensuring that they will be rewarded the bounty upon completing the task, but I'm not really sure the best way of doing that. So if you have any good ideas relating to that let me know.

You could use an escrow service for that.

[bitfreak!]

Also, I feel like developers will be much more willing to work on fulfilling these bounties if I can provide some way of ensuring that they will be rewarded the bounty upon completing the task, but I'm not really sure the best way of doing that. So if you have any good ideas relating to that let me know.

You could use an escrow service for that.

Can you expand on how that would work and what services I should take a look at?

[BitcoinFr34k]

An escrow service is basically a middle man. You send them the money in advance and they will hold it until someone completes the job. Then they will transfer the money to that person. If a set date expires without someone completing the job they will transfer the money back to you.

The forum has several trusted escrow members like JohnHamilton and escrow.ms. Click their names to visit their threads. You can also view their user profiles to see whst feedback they have received from previous transactions.

Hope this helps and good luck with your project. Too bad I can't code

[Cryddit]

There is a bit of problem with the mini-blockchain idea as presented here. 

A blockchain is secured by the work of finding preimages for hashes.  That's what you need to do in order to build a blockchain from least recent to most recent.  However, going the other way, you just need to start with the 'preimage' you want, plug in some arbitrarily chosen nonce, and run the hash function once.   So you could fabricate a supposed 'recent' block and then, with very little effort, construct a fake chain that leads back from it -- to the full length of your mini-blockchain.

So here is the issue.  An attacker can present hundreds of bogus mini-blockchains per second and the client has to figure out which one is real.  In the absence of a way to check things back to the Genesis Block, that's difficult.

I'm not saying the problem isn't solvable.  It's just kinda non-obvious.  One thing you need to do is to make sure it's more computationally expensive to create new blocks backward than it is forward.

[bitfreak!]

So here is the issue.  An attacker can present hundreds of bogus mini-blockchains per second and the client has to figure out which one is real.  In the absence of a way to check things back to the Genesis Block, that's difficult.

I'm not sure that you fully understand the concept, the mini-blockchain is exactly the same as a normal blockchain except that after a certain number of blocks the transactions are pruned from the blocks. The remaining block headers form the proof chain and the proof chain feeds into the mini-blockchain, and that makes it simple to verify the mini-blockchain against the proof chain (meaning the proof chain with the highest cumulative difficulty). You can check the proof chain all the way back the genesis block, you just cannot check the transactions all the way back the genesis block because the transactions are discarded after I certain period of time like I just mentioned. The way that address balances are maintained without a record of every transaction which ever occurred is via the Account Tree. The only attack I know which could get around the security of this design is the Secret Chain Attack documented on the Weaknesses and Attack Vectors page of the wiki.

[bitfreak!]

Hope this helps and good luck with your project.

Thanks for the information, I'll look into the escrow option further.

[BitcoinFr34k]

Hope this helps and good luck with your project.

Thanks for the information, I'll look into the escrow option further.

No problem. Make sure to use a trusted member. $20,000 is a lot of money . Escrow.ms is a well known and experienced member.

[bitfreak!]

Hope this helps and good luck with your project.

Thanks for the information, I'll look into the escrow option further.

No problem. Make sure to use a trusted member. $20,000 is a lot of money . Escrow.ms is a well known and experienced member.

Yeah that's what worries me, I'm not really sure how safe it would be to trust anyone with $20,000 worth of BTC. And as I mentioned, the final reward will be calculated by the exchange rate at he time the bounty is filled, so I'm not sure how that would work with escrow.

[CIYAM]

You would be welcome to create a project on CIYAM Open for this (https://ciyam.org/open) - it has a workflow process that locks in a chosen dev for a period of time (so no-one is wasting their efforts rushing to get a bounty) and for this project I would not charge any fee.

If the dev fails to deliver by the date and time that they had promised to then the task can be re-opened.

This is being used for the Moneychanger project as well as for the CIYAM project itself.

Also if you need an escrow then for a small fee I'd be happy to do this (check my trust rating).

[BitcoinFr34k]

I think escrow.ms is a good choice. Here is his trust record: https://bitcointalk.org/index.php?action=trust;u=76380

He recently escrowed a 18 BTC deal, so he's experienced with larger amounts of BTC. You could send him a PM and try to figure out how you are planning on doing it.

[bitfreak!]

You would be welcome to create a project on CIYAM Open

Thanks for the offer, but the problem is finding developers skilled enough to work on a project like this. That's why I created a bounty in the first place, because I found it very difficult to put together a team of developers skilled enough to work on this project. If there is a team of developers out there who think they can get the job done then I am more than willing to that route. And I will also keep your escrow offer in mind, because you strike me as some one I can trust to get the job done.

[Baldassare]

I'm working on a similar idea, but with only two components: account tree and proof chain. Also writing in python. Project is progressing, should be done in a few month.
Not really interested in the bounty.

[cxboyminer]

I know how to code HTML, CSS..., but not professional. If you can tell me a way to learn them quick and thoroughly I am more than happy to do that.

Good luck on your request

p.s. USE ESCROW!!!

[bitfreak!]

I'm working on a similar idea, but with only two components: account tree and proof chain. Also writing in python. Project is progressing, should be done in a few month.
Not really interested in the bounty.

Well it does not necessarily have to be written in one of the languages I specified. If you can get the basic concept implemented without the extra components you will still be eligible for the first bounty.

[Baldassare]

Cool, I will be watching this thread and will report if I've made any progress.
Good luck by the way. This is the right direction for altcoins to take.

[bitfreak!]

Great... moved to the alt-coin section. Now this thread has every chance in the world of being noticed by decent developers... 

[CIYAM]

Great... moved to the alt-coin section. Now this thread has every chance in the world of being noticed by decent developers... 

Don't worry too much - it's happened to other projects that have still ended up getting devs - I think that the "idea" more than where it is categorized will determine the result.

[bitfreak!]

Thanks for the encouragement, I'm just not very optimistic anymore because I've been trying to find developers for this project for many months now. And this thread was already on the 5th page of the alt-coin section before I even noticed it was moved, which is extremely discouraging. Gaaahhh I guess I'll just have to suck it up and hope for the best.